Having the copts set on a per-target level can lead to ODR violations
in some cases. Avoid this by ensuring the regex engine is picked
through compiler intrinsics in the header directly.
* Add myself to CONTRIBUTORS under the corp CLA for Stripe, Inc.
* Add support for building with Bazel.
Limitations compared to existing CMake rules:
* Defaults to using C++11 `<regex>`, with an override via Bazel flag
`--define` of `google_benchmark.have_regex`. The TravisCI config sets
the regex implementation to `posix` because it uses ancient compilers.
* Debug vs Opt mode can't be set per test. TravisCI runs all the tests
in debug mode to satisfy `diagnostics_test`, which depends on `CHECK`
being live.
* Set Bazel workspace name so other repos can refer to it by stable name.
This is recommended by the Bazel style guide to avoid each dependent
workspace defining its own name for the dependency.
